Process for the production of kerosene and diesel fuels from light unsaturated fractions and btx-rich aromatic fractions

ABSTRACT

Process for the production of kerosene and diesel fuels from a so-called light cracked naphtha fraction, to which can be added any quantity of an LPG fraction and a BTX-rich aromatic fraction and which uses a stage for oligomerization of olefins and alkylation of olefins on the aromatic compounds.

INTRODUCTION

The evolution of automotive engines actually results in an increase in the demand for diesel fuel at the expense of that of gasoline.

The forecasts relating to the evolution of the market for automotive fuels indicate an almost generalized reduction throughout the world in the demand for gasoline.

Thus, whereas in 2000, the ratio of gasoline consumption relative to diesel fuel was 2, it is expected that it will be close to 1.5 in 2015.

For the European Union, this reduction is extremely high, since this ratio that was 1 in 2000 should shift to 0.5 in 2012 and even drop further beyond.

Furthermore, the demand for kerosene should also significantly increase in the coming years in connection with the evolution of the market of air transport.

This inevitable evolution toward an increased demand for middle distillates and the reduction of the demand for gasoline poses to the refining industry a serious problem of adaptation of supply to demand, and this within a very short time period that is not very compatible with the construction of new installations that are expensive and take a long time to come on stream, such as vacuum hydrocracking of diesel fuel.

This invention proposes an attractive approach that makes it possible, starting from light cracked naphtha (optionally including any proportion of olefinic fractions C3 and C4 called “LPG”), and a BTX-rich aromatic fraction, to answer an increased demand for diesel fuel and kerosene, without involving new and expensive hydrocracking units.

The approach described in this invention is particularly well suited to the remodeling of existing refining units.

PRIOR ART

In a market that is dominated by the consumption of gasoline, as is the case in, for example, the United States, the production of diesel fuel is essentially ensured starting from so-called “straight run” middle distillates, i.e., originating from the direct distillation of crude petroleum.

These middle distillates should be hydrotreated to meet the now very strict specifications of sulfur content (10 ppm maximum) and aromatic compound contents. Currently, this production is notoriously inadequate and requires the refiners in certain geographic zones, and in particular Europe, to import diesel fuel to meet domestic demand.

Conversely, and particularly in Europe, the refiners deal with gasoline waste whose exports in the deficient geographic zones are uncertain over the short term due to the increase in refining capacities and/or the reduction in consumption in the zones that are involved.

For all of these reasons, a certain number of refiners have built hydrocracking installations that make it possible to transform heavy fractions, such as vacuum diesel fuel, into diesel fuel of very good quality. Nevertheless, this process is very expensive in investment and utilities because it operates at very high pressure (greater than 100 bar) and results in a very high consumption of hydrogen (on the order of 10 to 30 kg of hydrogen per ton of feedstock), making it necessary to establish a specific installation for the production of hydrogen.

Other less expensive approaches for producing diesel fuel can be considered, namely the oligomerization of light olefins that have 3 to 6 carbon atoms, for example originating from catalytic cracking. However, these olefinic fractions very often contain sulfur-containing and nitrogen-containing impurities that quickly deactivate the oligomerization catalyst and can make the process less economical. It is therefore necessary to purify the oligomerization feedstock. This is done by adding cleaning equipment, most often in several stages, including diverse, regenerative or non-regenerative adsorbent compounds.

This approach can be defined as an alternative to the “hydrocracking” approach, relying on an oligomerization of light olefins of 3 to 10 carbon atoms, in a preferred manner 4 to 6 carbon atoms, coupled to an alkylation of olefins of 8 to 10 carbon atoms, not having reacted to the oligomerization on a BTX-rich fraction, generally available starting from a semi-regenerative or regenerative reforming.

This alkylation culminates in a fraction that is located in the range of middle distillates (diesel fuel or kerosene) that it is then necessary to hydrotreat and/or hydrogenate to culminate in commercial products.

The approach that is an object of this invention remains economically much less expensive than the hydrocracking approach in terms of investment, utilities and hydrogen consumption, and it leads to a reduction of gasoline and an increase in distillate in the same order of magnitude.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of one embodiment of the invention.

SUMMARY DESCRIPTION OF THE INVENTION

This invention describes a process for the production of diesel fuel (13) from a gasoline fraction (1) that originates from a catalytic cracking unit and a BTX fraction (9) that originates from a unit for catalytic reforming of gasolines, relying on the concatenation of the following stages:

-   -   An optional stage 1 for selective hydrogenation (SHU) of the         initial gasoline fraction,     -   A stage 2 for treatment on the acid catalyst (TR) of the         effluent that is obtained from stage 1,     -   A stage 3 for distillation of the effluent of stage 2 that is         produced in a first distillation column (CD1) that makes it         possible to separate at the top an olefinic fraction (4) that         has a final boiling point of approximately 60°, intermediately a         distillation interval fraction (5) of between 60° C. and 150°         C., and at the bottom a boiling point fraction (6) that is         greater than 150° C., which is sent to a hydrotreatment (HDT)         unit, with the effluent (12) of the hydrotreatment unit being         sent to a total hydrogenation (HT) unit that produces the         desired diesel fuel (13),     -   A stage 4 for oligomerization (OLG) of the olefinic fraction (4)         optionally mixed with an LPG fraction (10) that contains         olefins, from which, after distillation, a stream (7) of         oligomerized olefins with a number of carbon atoms that ranges         from 8 to 20 is extracted and which is sent for a first part via         the stream 7 a to the hydrotreatment (HDT) unit that constitutes         the stage (6) and for a second part via the stream 7 b to the         total hydrogenation (HT) unit,     -   A stage 5 for alkylation of the stream (8) of olefins into C3         and C8 on the BTX fraction (9), whereby the effluent (11) of the         alkylation (ALK) unit is sent into a second distillation column         (CD2) from which 3 fractions are extracted:     -   A gasoline fraction (11 a)—with a boiling point that is less         than 100° C.—that is sent to the gasoline pool,     -   An intermediate fraction (11 b) with a distillation interval of         between 100° C. and 150° C., essentially consisting of BTX that         has not reacted, which is for the most part recycled at the         input of the alkylation (ALK) unit, with the exception of a         fraction that constitutes the purging of said (ALK) unit, which         is itself sent to the gasoline pool after stabilization,     -   A heavy fraction (11 c) with a boiling point that is greater         than 150° C. that is sent to the total hydrogenation (HT) unit         from which the desired diesel fuel (13) is extracted.

The gasoline fraction that constitutes the feedstock (1) is generally a catalytic cracking gasoline that contains 5 to 10 carbon atoms and in a preferred manner 5 to 7 carbon atoms.

According to a preferred variant of the process according to this invention, the acid catalyst treatment (TR) stage 2 relies on an ion-exchange resin-type acid catalyst, or supported phosphoric acid catalyst, or any acid catalyst previously used in the downstream stages of oligomerization (OLG) or alkylation (ALK) in a temperature range of 20° C. to 350° C., in a preferred manner 40° C. to 250° C., and in a pressure range of 1 bar to 100 bar, in a preferred manner 10 to 30 bar, and in a VVH range of 0.1 h-1 to 5 h-1, in a preferred manner 0.3 h-1 to 2.0 h-1.

It is recalled that 1 bar=10⁵ Pascal and that the VVH refers to the ratio between the volumetric flow rate of feedstock and the volume of catalyst.

According to another preferred variant of the process according to this invention, the oligomerization stage 4 is supplied by the cracking gasoline (4) and an LPG fraction that contains olefins and works on a preferably zeolitic- or silica alumina-type acid catalyst in a temperature range of 20° C. to 400° C., in a preferred manner from 100° C. to 350° C., and in a pressure range of 1 to 100 bar, in a preferred manner 20 to 70 bar, and in a VVH range of 0.1 h-1 to 5 h-1, in a preferred manner 0.2 h-1 to 1.0 h-1.

According to a preferred variant of the process according to this invention, alkylation stage 5 (ALK) is supplied by the effluent (8) of the oligomerization (OLG) unit and by a fraction that is rich in aromatic compounds (9) containing 6 to 12 carbon atoms, and in an also preferred manner 6 to 9 carbon atoms, and it works on a preferably zeolitic- or silicoaluminate-type acid catalyst, in a temperature range of 20° C. to 400° C., in a preferred manner 100° C. to 350° C., and in a pressure range of 1 bar to 100 bar, in a preferred manner 20 bar to 70 bar, and in a VVH range of 0.05 h-1 to 5 h-1, in a preferred manner 0.1 h-1 to 2.0 h-1.

According to another preferred variant of the process according to this invention, the hydrotreatment (HDT) stage 6 uses a catalyst that contains at least one metal that is selected from among Ni, Co and Mo and operates in a temperature range of 50° C. to 400° C., in a preferred manner 100° C. to 350° C., and in a pressure range of 1 bar to 100 bar, in a preferred manner 20 bar to 70 bar, and in a VVH range of 0.1 h-1 to 10 h-1, in a preferred manner 0.5 h-1 to 5.0 h-1.

According to another variant of the process according to this invention, the hydrotreatment (HDT) stage 6 uses a catalyst that contains at least one metal that is selected from among Pd and Pt and operates in a temperature range of 50° C. to 300° C., in a preferred manner from 100° C. to 250° C., and in a pressure range of 1 bar to 100 bar, in a preferred manner from 20 bar to 70 bar, and in a VVH range of 0.1 h-1 to 10 h-1, in a preferred manner from 0.5 h-1 to 5.0 h-1.

Finally, according to a last variant of the process according to this invention, stage 2 for acid catalyst treatment (TR) is preceded by a selective hydrogenation (SHU) stage 1 of the initial gasoline fraction.

DETAILED DESCRIPTION OF THE INVENTION

This invention describes a process for producing kerosene or diesel fuel from olefinic fractions that are typically obtained from a unit for catalytic cracking of gasolines (denoted FCC in abbreviated form) and a BTX-rich fraction (abbreviation of benzene, toluene, xylene) typically obtained from a semi-regenerative or regenerative reforming unit, generally present on the same site as the FCC unit.

“Typically” is defined as the most common case that does not exclude other sources as described below.

The olefinic fraction can also originate from steam-cracking-type units (denoted SC in abbreviated form), Fischer-Tropsch synthesis units (denoted FT in abbreviated form), coking units (denoted CK in abbreviated form), or else a visco-reduction unit (denoted VB in abbreviated form). The BTX-rich fraction can also originate from a steam-cracking (SC) unit, a vaporeforming unit (denoted VR in abbreviated form), an olefin cracking unit (denoted CO in abbreviated form), or else a unit that transforms methanol into olefins (denoted MTO in abbreviated form).

The feedstock to be treated (1) is a distillation interval gasoline that is between 30° C. and 250° C. This feedstock is optionally sent into an SHU unit that makes it possible to hydrogenate the gum-generating unsaturated hydrocarbons selectively, such as the diolefins.

The treated effluent (2) is sent directly or after distillation into a treatment (TR) unit that is based on the use of an acid catalyst, preferably an ion-exchange resin-type catalyst as described in the patent FR 2,840,620, or of the supported phosphoric acid type.

This stage has as its object to capture compounds that poison the acid catalysts, in particular the nitrogen-containing compounds, and optionally to transform them into heavier compounds.

It has actually been observed, surprisingly enough, that the catalysts cited above, after a period of almost total capture of the nitrogen-containing compounds, continue to convert the nitrogen-containing compounds of the feedstock into heavier compounds in such a way that if distillation is established downstream from the treatment, the light fraction that is obtained at the top of the distillation column is low in nitrogen. This light top fraction can be treated without additional purification on the downstream acid catalysts.

An increasing of the weight of the sulfur-containing compounds in such a way that the light fraction obtained from the downstream distillation is also low in sulfur-containing compounds was also observed in this treatment (TR) stage.

The effluent (3) of the unit for treatment with resins (TR) is sent into a distillation column (CD1) from which 3 fractions are extracted:

a) A top fraction corresponding to the stream (4) that is sent into the concatenation of oligomerization (OLG)-BTX alkylation (ALK) units for the purpose of producing a diesel-fuel-type distillation interval fraction (11) that is hydrogenated in the total hydrogenation (HT) unit for producing the desired distillate (13),

b) An intermediate fraction (5) that can be sent into a hydrodesulfurization unit that makes it possible to reduce the sulfur content to less than 10 ppm (not shown in FIG. 1).

This type of unit is, for example, the unit known commercially under the name of Prime G+, marketed by the AXENS Company, whose description can be found in the patent FR 2,797,639.

c) A bottom fraction (6) that is sent into a strict hydrotreatment (HDT) unit that makes it possible to reduce the sulfur content to less than 10 ppm, to hydrogenate almost all of the olefins, and to reduce significantly the content of aromatic compounds. The effluent of the hydrotreatment (HDT) unit, denoted stream (12), is sent to the total hydrotreatment (HT) unit.

The top fraction (4), optionally mixed with an LPG fraction (10), is sent into an oligomerization (OLG) unit that will form oligomers with a number of carbon atoms of between 8 and 20 constituting the stream (7).

Based on its sulfur content, this stream (7) is:

-   -   Either sent (stream 7 a) to the hydrotreatment (HDT) unit, when         its sulfur content is greater than 10 ppm,     -   Or sent (stream 7 b) to the total hydrogenation (HT) unit when         its sulfur content is less than 10 ppm.

The oligomerization (OLG) unit preferably operates on a zeolitic- or silica-alumina-type acid catalyst, in a temperature range of 20° C. to 400° C., in a preferred manner 100° C. to 350° C., and in a pressure range of 1 bar to 100 bar, in a preferred manner 20 bar to 70 bar, and in a VVH range of 0.1 h-1 to 5 h-1, in a preferred manner 0.2 h-1 to 1.0 h-1.

The light olefin fraction, with a boiling point that is less than 150° C., not having reacted in the oligomerization (OLG) unit, constitutes the stream (8) that supplies the alkylation (ALK) unit that relies on a BTX fraction (9) that is generally obtained from a regenerative reforming unit of the gasolines.

The unit for alkylation of olefins (8) obtained from the oligomerization (OLG) unit on the BTX fraction (9) preferably operates on a zeolitic- or silicoaluminate-type acid catalyst in a temperature range of 20° C. to 400° C., in a preferred manner 100° C. to 350° C., and in a pressure range of 1 bar to 100 bar, in a preferred manner 20 bar to 70 bar, and in a VVH range of 0.05 h-1 to 5 h-1, in a preferred manner 0.1 h-1 to 2.0 h-1.

The effluent (11) of the alkylation (ALK) unit is sent into a distillation column (CD2) from which 3 fractions are extracted:

-   -   A gasoline fraction (11 a)—with a boiling point that is less         than 100° C.—that is sent to the gasoline pool,     -   An intermediate fraction (11 b) with a distillation interval of         between 100° C. and 150° C., essentially consisting of BTX that         has not reacted and that is for the most part recycled at the         input of the alkylation unit, with the exception of a fraction         that constitutes the purging of the unit, and that is itself         sent to the gasoline pool after stabilization,     -   A heavy fraction (11 c) with a boiling point that is greater         than 150° C. that is sent to the total hydrogenation (HT) unit         from which the desired diesel fuel (13) is extracted.

Example

The following example illustrates the process according to the invention.

The starting material is a feedstock that consists of a catalytic cracking gasoline and a BTX fraction that originates from a catalytic reforming unit. An LPG fraction that originates from the catalytic cracking unit is also added.

The mass flow rates of the components of the feedstock are as follows:

Gasoline (1): 100 t/h

BTX fraction (9): 18 t/h

LPG fraction (10): 25 t/h

The gasoline (1) is introduced into a selective hydrogenation unit (SHU) that operates under the following conditions:

-   -   Pressure: 15 bars effective     -   Temperature 120° C.     -   HR 945 catalyst marketed by the Axens Company, with a VVH of 2         h-1.

The hydrogenated gasoline (2) is introduced in an acid catalyst treatment (TR) unit that operates under the following conditions:

-   -   Pressure: 15 bars effective     -   Temperature 100° C.     -   TA 801 catalyst marketed by the Axens Company, with a VVH of 0.5         h-1.

The effluent (3) of the TR unit is introduced into a distillation column (CD1) from which the following are separated:

-   -   At the top, an olefinic fraction (4) that has a final boiling         point of 60° C.,     -   Intermediately, a distillation interval fraction (5) that is         between 60° C. and 150° C.,     -   At the bottom, a boiling point fraction (6) that is greater than         150° C.

The top fraction (4) is mixed with a certain quantity of the LPG fraction (10), and the resulting mixture is introduced into the oligomerization (OLG) unit that operates under the following conditions:

-   -   Pressure: 60 bars effective     -   Temperature: 160° C.     -   IP 811 catalyst marketed by the Axens Company, with a VVH of 0.5         to 2 h-1.

The oligomerization (OLG) unit produces, on the one hand, an effluent (7) that consists of oligomerized olefins and that is sent in part (7 a) in a mixture with the bottom fraction (6) of the distillation column (CD1) into a hydrotreatment (HDT) unit that operates under the following conditions:

-   -   Pressure: 20 bars effective     -   Temperature 300° C.     -   HR 506 catalyst that is marketed by the Axens Company, used with         a VVH of 1 h-1.

The effluent (12) of the hydrogenation (HDT) unit is sent to the total hydrogenation (HT) unit, optionally mixed with the part (7 b) of the olefinic effluent (7).

The effluent (13) of the total hydrogenation (HT) unit constitutes the production of desired diesel fuel with the following specifications:

Engine cetane number: 45

Density 0.775 kg/m3

The intermediate effluent (5) of the distillation column CD1 is sent to the gasoline pool.

The oligomerization (OLG) unit also produces an effluent (8) of olefins in C3 and C4 that is sent with the BTX fraction (9) into an alkylation (ALK) unit that works under the following conditions:

-   -   Pressure 2,500 kPa (k is the abbreviation of kilo or 10³ pascal)     -   Temperature 150° C.     -   Y zeolite catalyst     -   VSL: 2.5 h-1.

The effluent (11) of the alkylation (ALK) unit is sent into a second distillation column (CD2) that produces at the bottom an effluent (11 c) that is sent into the total hydrogenation (HT) unit and therefore contributes to the production of the desired diesel fuel (13).

The lateral effluent (11 b) of the distillation column (CD2) is sent to the alkylation (ALK) unit.

The top effluent (11 a) of the column CD2 is sent to the gasoline pool.

Tables A and B below provide the detail of streams according to the diagram of FIG. 1.

Overall, the process according to the invention therefore produced 66 tons/hour of diesel fuel (13), starting from 100 tons/hour of FCC gasoline (1), 18 tons/hour of BTX fraction (9), and 25 t/h of the LPG fraction of FCC (10), or a yield (13)/(1)+(9)+(10) of 46% transformation of a gasoline fraction into a distillate fraction, usable as a base of kerosene or diesel fuel.

To understand Tables A and B, we will spell out the meanings of the abbreviations that are used:

Cn refers to a paraffinic fraction with n carbon atoms

Cn⁼ refers to an olefinic fraction with n carbon atoms

A refers to aromatic compounds

B refers to benzene

T refers to toluene, and X refers to xylenes

The indices n, i, and c respectively mean normal (or linear), iso (or branched) and cyclic.

TABLEAU “A” Effluent Effluent CD1 CD1 CD1 Feed Oligo Oligo Oligo Oligo Feed SHU TR lights heart cut heavy cut C4 Feed Prod heavies lights (1) (2) (3) (4) (5) (6) (10) (10) + (4) (8) + (7) (7) (8) C4(i, n) 0.05 0.08 0.08 0.08 — — 12.00 12.06 12.08 — 12.08 C4= 0.27 0.24 0.22 0.22 — — 13.00 13.22 0.68 — 0.66 C5(i, n, c) 10.49 11.14 11.34 11.14 — — — 11.14 11.14 — 11.14 C5= 13.10 12.74 11.47 11.47 — — — 11.47 1.72 — 1.72 C6(i, n, c) 8.57 8.77 8.77 0.88 7.90 — — 0.88 0.88 — 0.88 C6= 8.34 8.13 8.13 0.81 7.32 — — 0.81 0.20 — 0.20 B 0.94 0.94 0.94 — 0.94 — — — — — — C7(i, n, c) 6.28 6.28 6.28 — 6.28 — — — — — — C7= 3.61 3.61 3.01 — 3.61 — — — — — — T 4.87 4.87 4.87 — 4.87 — — — — — — C8(i, n, c) 4.09 4.09 4.09 — 4.09 — — — — — — C8= 1.64 1.64 1.64 — 1.64 — — — — — — X 9.70 9.70 9.70 — 9.70 — — — — — — C9(i, n, c) 1.85 1.85 1.85 — 0.58 1.30 — — — — — C9= 1.25 1.26 1.26 — 0.38 0.89 — — — — — A9 9.93 9.93 9.93 — 1.49 6.44 — — — — — C10(i, n, c) 1.90 1.90 1.90 — — 1.80 — — — — — C10= 0.84 0.84 0.84 — — 0.84 — — — — — A10 7.88 7.88 7.86 — — 7.88 — — — — — C11(i, n, c) 0.57 0.57 0.57 — — 0.57 — — — — — C11= 0.70 0.70 0.70 — — 0.70 — — — — — A11 1.28 1.28 1.28 — — 1.28 — — — — — C12(i, n, c) 0.46 0.46 0.46 — — 0.46 — — — — — C12= 0.14 0.14 0.14 — — 0.14 — — — — — A12 0.89 0.89 0.89 — — 0.89 — — — — — C12(i, n, c) 0.02 0.02 0.02 — — 0.02 — — — — — C12= — — — — — — — — — — — A12 0.01 0.01 0.01 — — 0.01 — — — — — Oligomères — — 1.30 — 1.30 — — — 17.19 — 17.19 C8-C12 Oligomères — — — — — — — — 5.73 5.73 — C12-C16 Alkylate — — Dienes 0.33 0.03 0.03 — — 0.03 — — — — — HT oligomere — — C12-C15 HT Alkylate — — S(ppm pds) 1000 800 800 8 320 472 10 9 9 78 0 N(ppm pds) 30 27 14 0 3 11 1 1 1 5 0 Total 100.00 100.00 100.00 24.60 50.06 25.35 25.00 49.60 49.60 5.73 43.87 [Key to Table A:] TABLEAU “A” = TABLE “A” Oligomères C8-C12 = C8-C12 Oligomers Oligomères C12-C16 = C12-C16 Oligomers

TABLEAU “B” HDT HDT Effluent Effluent (après (après BTX Heart Oligo Oligo strippeur) strippeur) Feed recycle Alky Light cut Heavy Heart cut Heavies Heavies (H2 feed non HT feed (H2 feed non BTX (11b) effluent purge purge Product to gasoline to HDT to HT exemplifiè) (7b + exemplifiè) (9) recycle (11) (11a) (11b) (11c) (11b)out (7a) (7b) (12a) 12 + 11c) (13) C4(i, n) — — 12.08 12.08 — — — — — — — — C4= — — 0.01 0.01 — — — — — — — — C5(i, n, c) — — 11.14 11.14 — — — — — — — — C5= — — 0.02 0.02 — — — — — — — — C6(i, n, c) — — 0.88 0.88 — — — — — — — — C6= — — 0.00 0.00 — — — — — — — — B — — — — — — — — — — — — C7(i, n, c) — — — — — — — — — — — — C7= — — — — — — — — — — — — T 14.00 68.55 70.67 — 70.67 — 2.12 — — — — — C8(i, n, c) — — — — — — — — — — — — C8= — — — — — — — — — — — — X 4.00 1.29 1.33 — 1.33 — 0.04 — — — — — C9(i, n, c) — — — — — — — — — 1.29 1.29 8.40 C9= — — — — — — — — — 0.80 0.90 — A9 — — — — — — — — — 8.44 8.44 4.22 C10(i, n, c) — — — — — — — — — 1.58 1.85 6.68 C10= — — — — — — — — — 0.76 0.76 — A10 — — — — — — — — — 7.88 7.88 3.84 C11(i, n, c) — — — — — — — — — 0.64 0.54 1.91 C11= — — — — — — — — — 0.63 0.83 — A11 — — — — — — — — — 1.28 1.28 0.64 C12(i, n, c) — — — — — — — — — 0.47 0.47 1.05 C12= — — — — — — — — — 0.13 0.13 — A12 — — — — — — — — — 0.89 0.89 0.45 C12(i, n, c) — — — — — — — — — 0.02 0.02 0.02 C12= — — — — — — — — — — — — A12 — — — — — — — — — 0.01 0.01 0.03 Oligomères — 3.64 3.75 — 3.75 — 0.11 — — — — — C8-C12 Oligomères — — 0.42 — — 0.42 — — 5.73 — 8.15 — C12-C16 Alkylate — — 36.05 — 0.00 35.05 0.00 — — — 35.06 — Dienes — — — — — — — — — 0.03 0.03 — HT oligomere 6.15 C12-C15 HT Alkylate 35.09 S(ppm pds) 0 0 0 0 0 0 0 0 70 12 11 1 N(ppm pds) 0 0 0 0 0 0 0 0 5 5 2 1 Total 18.00 73.48 136.36 24.12 76.75 36.47 2.27 — 5.73 25.35 68.55 66.51 [Key to Table B:] TABLEAU “B” = TABLE “B” HDT Effluent (après strippeur) (H2 feed non exemplifié) = HDT Effluent (after stripper)(H2 feed not shown) Oligomères C8-C12 = C8-C12 Oligomers Oligomères C12-C16 = C12-C16 Oligomers

Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.

The entire disclosures of all applications, patents and publications, cited herein and of corresponding French application No. 10/03559, filed Sep. 7, 2010, are incorporated by reference herein.

From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. 

1) Process for the production of diesel fuel from a gasoline fraction that contains 5 to 10 carbon atoms and in a preferred manner 5 to 7 carbon atoms originating from a catalytic cracking unit (1), and a BTX fraction (9) that typically originates from a unit for catalytic reforming of gasolines, relying on the concatenation of the following stages: A stage 1 for selective hydrogenation (SHU) of the initial gasoline fraction, A stage 2 for treatment on the acid catalyst (TR) of the effluent that is obtained from stage 1, A stage 3 for distillation of the effluent of stage 2 that is produced in a first distillation column (CD1) that makes it possible to separate at the top an olefinic fraction (4) that has a final boiling point of approximately 60°, intermediately a distillation interval fraction (5) of between 60° C. and 150° C., and at the bottom a fraction (6) with a boiling point that is greater than 150° C., which is sent to a hydrotreatment (HDT) unit, A stage 4 for oligomerization (OLG) of the olefinic fraction (4), optionally mixed with an LPG fraction (10) that contains olefins, from which, after distillation, a stream (7) of oligomerized olefins that constitutes a “kero” fraction that is sent for a first part (7 a) to the hydrotreatment (HDT) unit and for a second part (7 b) to a total hydrogenation (HT) unit is extracted, A stage 5 for alkylation of the stream (8) of olefins into C3 and C4 obtained from stage 4 for oligomerization on the BTX fraction (9) that is rich with aromatic compounds containing 6 to 12 carbon atoms, and in a preferred manner 6 to 9 carbon atoms, whereby the effluent (11) of the alkylation (ALK) unit is sent into a second distillation column (CD2) from which 3 fractions are extracted: A gasoline fraction (11 a) with a boiling point that is less than 100° C., which is sent to the gasoline pool, An intermediate fraction (11 b) with a distillation interval of between 100° C. and 150° C., essentially consisting of BTX that has not reacted, which is for the most part recycled at the input of the alkylation unit, with the exception of a fraction (11 d) that constitutes the purging of the (ALK) unit, and which is itself sent to the gasoline pool after stabilization, A heavy fraction (11 c) with a boiling point that is greater than 150° C. that is sent to the total hydrogenation (HT) unit from which the desired diesel fuel (13) is extracted, with the oligomerization stage 4 working on a preferably zeolitic- or silica-alumina-type acid catalyst, in a temperature range of 100° C. to 350° C., and in a pressure range of 20 to 70 bar, and in a VVH range of 0.2 to 1.0 h-1, and with alkylation stage 5 working on a preferably zeolitic- or silicoaluminate-type acid catalyst in a temperature range of 100 to 350° C., and in a pressure range of 20 to 70 bar, and in a VVH range of 0.1 h-1 to 2.0 h-1. 2) Process for the production of diesel fuel according to claim 1, in which the stage 2 for treatment on an acid catalyst relies on an ion-exchange resin-type acid catalyst, or supported phosphoric acid catalyst, or any acid catalyst previously used in the downstream stages of oligomerization (OLG) or alkylation (ALK), in a temperature range of 20° C. to 350° C., in a preferred manner of 40 to 250° C., and in a pressure range of 1 to 100 bar, in a preferred manner 10 to 30 bar, and in a VVH range of 0.1 to 5 h-1, in a preferred manner 0.3 to 2.0 h-1. 3) Process for the production of distillates according to claim 1, in which the hydrotreatment (HDT) stage uses a catalyst that contains at least one metal that is selected from among Ni, Co and Mo and operates in a temperature range of 50 to 400° C., in a preferred manner 100 to 350° C., and in a pressure range of 1 to 100 bar, in a preferred manner 20 to 70 bar, and in a VVH range of 0.1 h-1 to 10 h-1, in a preferred manner 0.5 h-1 to 5.0 h-1. 4) Process for the production of distillates according to claim 1, in which the hydrotreatment (HDT) stage uses a catalyst that contains at least one metal that is selected from among Pd and Pt and operates within a temperature range of 50 to 300° C., in a preferred manner 100° C. to 250° C., and in a pressure range of 1 to 100 bar, in a preferred manner 20 to 70 bar, and in a VVH range of 0.1 h-1 to 10 h-1, in a preferred manner 0.5 h-1 to 5.0 h-1. 